This invention relates to an upper main bearing removal tool and more particularly to a tool which is readily operable by one person to effect rapid removal of a main bearing without damage thereto. The tool is rugged and durable and has a relatively simple design and can be economically manufactured.
The present invention relates to bearing removal tools and is more particularly concerned with a tool for the removal of upper main bearings.
As is well known, internal combustion engines transmit the power generated by means of a crankshaft which is rotatably supported within a series of bearings designated as the main bearings of the engine. Such main bearings are generally horizontally split, the upper portion constituting the upper shell and the lower portion being referred to as the lower shell. The lower bearing shell is maintained in place by means of a bearing cap which is secured to stud members in the engine block. The bearing cap and lower shell is usually easily removable; however, the upper main bearing or upper shell is removable with greater difficulty. Frequently a bearing removal tool is employed which is inserted in the oil hole of the crankshaft. The Rookstool U.S. Pat. No. 2,639,498 discloses one such type of tool. With such a tool, the crankshaft must be rotated and these prior procedures often required the presence of more than one person. Further, the rear main bearing is customarily not provided with an oil hold thereby necessitating a time-consuming and laborious bearing removal procedure.
In order to avoid resort to the procedures which employed the crankshaft oil holes, partially because of the need for more than one person during the bearing removal, various other tools were developed. U.S. Pat. No. 3,886,644 issued June 3, 1975 to General Motors Corporation, for example, discloses a tool which is mountable on the engine block and employs a pawl and ratchet arrangement in the urging of the upper shell from the engine. Such a device, however, is complex in structure and, therefore, relatively expensive.
The Coleman U.S. Pat. No. 2,800,708, issued July 30, 1957 discloses a tool for removing bearings which is in the form of an elongated resilient metal strip having a transverse curvature over substantially its entire length within a straight position, the resilient metal strip being bendable to enter the space between the outer surface of a crankshaft and the inner surface of an engine block. With such a tool there would be difficulties in transmitting impact forces of sufficient magnitude, due to the flexibility of the metal strip. It would also be difficult to avoid damage to the bearing surfaces.
Tools designed for other purposes, such as the pick of the Kottas U.S. Pat. No. 3,406,412 and the drift bar of the Colvin U.S. Pat. No. 1,344,619, are not at all suitable for use in removal of an upper main bearing.